1. Field of the Invention
The present invention relates to a cartridge which is detachably mountable on an image forming apparatus such as a copying machine, a printer or the like using recording technologies such as electrophotographic recording, electrostatic recording and the like, and more particularly, to a cartridge which has a developer containing portion with an inner pressure regulating function.
2. Description of Related Art
Conventionally, a process cartridge system has been known in, e.g., an electrophotographic image forming apparatus. In the process cartridge system, a photosensitive member and a process means acting on the photosensitive member are integrally formed into a process cartridge, and the process cartridge is made detachably mountable on the main body of the image forming apparatus. According to such the process cartridge system, the image forming apparatus can be maintained by a user oneself without a serviceperson, whereby operability can be greatly improved. For this reason, the process cartridge system is widely used in the image forming apparatus.
In such the process cartridge, as shown in FIG. 17, a coupling member 11e is rotatably fit into a hole 11e1 of a lower frame 11b of a container-shaped toner frame 11, and the coupling member 11e has a circumferential groove 11e5. The coupling member 11e is prevented from coming off along the axial direction by a shaft snap ring 11e3 being fit into the groove 11e5. An arm 9b3 of a crank-shaped toner feed member 9b having a journal fit into a central hole 11e4 of the coupling member 11e is fitted into a slit 11e2 extending to the inner diameter of the coupling member 11e. 
The coupling member 11e is shaft-sealed by a felt member 80 that is fitted into the hole 11e1, and air can go in and out the toner frame 11 through the felt member 80 because the felt member 80 is air permeable.
As shown in FIGS. 18A and 18B, a conventional toner cap 11-1f has circumferential protruded ridges 11-2f which can be force-fit into a toner filling opening 11-1d of the toner frame 11 as indicated by arrows E.
In a developing device which is detachably mountable on the main body of the image forming apparatus, a toner container containing a developer and a developing member (e.g., a developing sleeve) disposed at the opening of the toner container are integrally constituted, and the opening of the toner container is sealed with a toner seal until the developing device is actually used. When the developing device is used, the toner seal is removed, and the developing device is then mounted on the main body of the image forming apparatus.
However, airtightness between the inside and the outside of the container is improved in recently developed toner containers as compared with the formerly developed toner containers. Further, the toner particles have been made finer to cope with image enhancement, and toner filling has become dense to cope with ecological concerns and decrease in cost. For these reasons, seal performance for the toner container has become increasingly severe.
Therefore, to cope with such a situation, an oil seal is used as an agitating shaft seal member in a toner container having an agitating mechanism. Thus, air permeability at the agitating shaft portion decreases, whereby airtightness of the toner container surely improves. In this regard, e.g., Japanese Patent Application Laid-Open No. 9-236977 discloses the related art.
On the other hand, if the airtightness of the toner container is too high, there is the risk that when the cartridge receives a shock when the cartridge is in physical distribution or is used, the air pressure in the toner container rises too much in such a use environment of high temperature or the like, whereby the toner container deforms and the seal portion is damaged.
In order to solve such problems, the applicant has proposed the cartridge having the function to regulate the inner pressure of the toner container in Japanese Patent Application Laid-Open Nos. 11-338234 and 2000-29296.
In the pressure regulating mechanism as described in these documents, a vent is provided on the part of the toner container, the vent is covered by a sheet-shaped filter, and the filter is welded to the toner container. By such the mechanism, air permeability is permitted while preventing the toner from leaking, and the inner pressure of the toner container is regulated.
However, since it is necessary to prevent the toner from leaking, it takes time to weld or adhere the sheet-shaped filter to the container.
The present invention is accomplished in consideration of the above problem, and an object thereof is to provide a cartridge which can suppress an increase of an inner pressure of a developer container while maintaining a seal of the container.
Another object of the present invention is to provide a cartridge which can suppress an increase of an inner pressure of a developer container while maintaining a seal of the container in a simple way.
Still another object of the present invention is to provide a cartridge which can suppress an increase of an inner pressure of a developer container while maintaining a seal of the container, even if a filter disposed on a vent is not welded or adhered to the container.
Still another object of the present invention is to provide a cartridge comprising:
a developer container; and
a pressure regulating means for regulating an air pressure in the developer container, the pressure regulating means including a hollow portion having a vent and an elastic filter being compressed into the hollow portion.
Still another object of the present invention is to provide a cartridge comprising:
a developer container, the developer container including a first frame and a second frame; and
a pressure regulating means, provided on the second frame, for regulating an air pressure in the developer container,
wherein the pressure regulating means includes a hollow portion having a vent and a filter being disposed in the hollow portion, and the first frame has a function to prevent the filter from coming off from the hollow portion.
Other objects of the present invention will become apparent by reading the following detailed description as referring to the attached drawings.